C - Reading from a Text File

/*
** File FILE_3.C
**
** Illustrates how to read from a file.
**
** The file is opened for reading. Each line is successively fetched
** using fgets command. The string is then converted to a long integer.
**
** Note that fgets returns NULL when there are no more lines in the file.
**
** In this example file ELAPSED.DTA consists of various elapsed times in
** seconds. This may have been the result of logging the time of events
** using an elapsed time counter which increments each second from the
** time the data logger was placed in service.
**
** Typical data in elapsed.dta might be;
**
** 65
** 142
** 1045
** 60493
** 124567
**
**
** Peter H. Anderson, 4 April, '97
*/
#include &ltstdio.h> /* required for file operations */
#include &ltconio.h> /* for clrscr */
#include &ltdos.h> /* for delay */
FILE *fr; /* declare the file pointer */
main()
{
int n;
long elapsed_seconds;
char line[80];
clrscr();
fr = fopen ("elapsed.dta", "rt"); /* open the file for reading */
/* elapsed.dta is the name of the file */
/* "rt" means open the file for reading text */
while(fgets(line, 80, fr) != NULL)
{
/* get a line, up to 80 chars from fr. done if NULL */
sscanf (line, "%ld", &elapsed_seconds);
/* convert the string to a long int */
printf ("%ld\n", elapsed_seconds);
}
fclose(fr); /* close the file prior to exiting the routine */
} /*of main*/